1. Field of the Invention
This invention relates to a cassette for holding positive film sheets for subsequent removal by film developing apparatus. It includes elements to minimize accidental film discharge and other elements for aligning film sheets for controlled film removal.
2. Description of the Prior Art
Self-developing film units as conventionally supplied by Polaroid Corporation of Cambridge, Mass. include a light-sensitive or negative sheet which is mated to a positive sheet having an image-receiving layer supported on one side thereof. Either before or after the negative sheet is exposed to light, it is mated to the positive sheet and a visible image is formed on the positive sheet by the rupture and discharge of a pod of developer liquid which is distributed in the space between an exposed negative and the image-receiving layer of the positive sheet to initiate image development by a diffusion transfer process. A diffusion transfer process need not be discussed as it is well known in the industry.
There are two conventional procedures for mating positive and negative film sheets. One involves a composite film unit with the positive and negative sheets being joined as one with the pod of developer liquid being mounted on its leading end in order to discharge liquid between the two sheets as the pod and sheets pass between a pair of rollers mounted within a camera, immediately following the exposure of the negative.
Another conventional way is to have the positive and negative sheets separately mounted with the pod of developer liquid being mounted on the leading end of the positive sheet. The negative is exposed and transported by whatever mechanism to developing apparatus where it is mated with the positive sheet and pod of developer liquid. Thereafter, rupturing of the pod and spreading of the developer liquid is performed in a conventional manner.
Problems exist in conventional apparatus involving the positive and negative cassettes holding separate positive or negative film sheets. These problems include the premature discharge of film sheets from the cassettes due to impacts caused by transportation and loading of the cassettes into the appropriate apparatus prior to film development.